THURSDAY, Dec. 4, 2003 (HealthDayNews) -- Middle-aged adults who drink moderate amounts of alcohol do not increase or decrease their risk for stroke, but they do show evidence of brain atrophy, researchers report.
"There is some evidence that moderate drinking might be protective for coronary heart disease, but the effect of drinking on the risk for stroke is still controversial," says Dr. Jingzhong Ding, a research associate at the Bloomberg School of Public Health at Johns Hopkins University.
To investigate, Ding and his colleagues collected data on 1,090 men and women, 55 years or older, who participated in the Atherosclerosis Risk in Communities Study. This community-based study looked into the cause and development of atherosclerosis.
The researchers used baseline data collected from 1987 to 1989 and conducted follow-up examinations every three years until 1995.
The subjects were asked to have a brain magnetic resonance imaging (MRI) scan between 1993 and 1995, says the report in the Dec. 4 online issue of Stroke.
Using MRI, the researchers were able to see the effect alcohol had on the brain, Ding says.
After the MRIs, Ding's team had neuroradiologists look for the presence of infarction, the extent of white matter lesions, and ventricular and sulcal size. The ventricular and sulcal areas of the brain are areas that contain only cerebrospinal fluid. As the brain shrinks, the amount of cerebrospinal fluid increases.
In addition, the subjects were asked to report how much alcohol they consumed. Based on their answers, they were divided into five groups: never drinkers, former drinkers, occasional drinkers (less than one drink per week), low drinkers (between one to six drinks per week), and moderate drinkers (seven to 14 drinks per week).
Ding's group also collected data on income, physical activity, cigarette smoking, cholesterol, hypertension, heart disease, diabetes and stroke.
"We found that moderate alcohol drinking is associated with brain atrophy, as seen by a significant increase in ventricular and sulcal size, but we did not find any evidence that moderate drinking caused white matter lesion or affected brain functioning," Ding says.
Ding says other studies show brain atrophy is associated with impaired cognitive function.
While moderate alcohol drinking may be good for coronary heart disease, it may not be good for the brain, he says. And for stroke, whether moderate drinking is good or bad is still not known, Ding adds.
Dr. Ralph Sacco, the director of the stroke and critical care division at Columbia University Medical Center, disagrees with the findings.
The protective effect of alcohol in reducing the risk of stroke has been shown in several large studies, Sacco says. "These studies have clearly shown the protective effects of mild to moderate amounts of alcohol in reducing stroke risk," he adds.
In terms of brain shrinkage, Sacco thinks of it as a risk/benefit issue. Drinking too much is bad, including increasing the risk of stroke and many other diseases, he says.
Balancing the risk and benefit, he says, means that to get the protective benefit of alcohol people may incur the risk of a small, clinically insignificant amount of brain shrinkage.
Furthermore, Sacco points out that brain shrinkage happens for many reasons, including age and nutrition. "It is difficult to determine how much brain shrinkage is caused by alcohol," he says.
"There are pros and cons to drinking, and one should be sure that one drinks protective amounts and not harmful amounts," Sacco notes. "I tell people if they are not drinking now, don't run out and start. But if you are drinking too much you need to drink less."
"I think that drinking up to two drinks a day is protective," Sacco adds.
More information
To learn more about causes and prevention of stroke, visit the American Stroke Association or the National Institute of Neurological Disorders and Stroke.
